Mio FUSE Heart Rate Training + Activity Tracker (Cobalt / Large) + Extra Mio Fuse Charging Pack This Kit Includes an Additional Mio Fuse Charging Pack For Your Mio FUSE Heart Rate Training + Activity Tracker Get EKG-accurate heart rate data from your wrist with no chest strap required. Track your all-day activity (steps, calories, &amp; distance) + workout tracking. &gt; Water resistant (30M). Features both Bluetooth Smart (4.0) and ANT+ transmission to mobile apps and sport devices. Size S/M: fits wrists 5.8&quot; - 7&quot;, Size L: fits wrists 6.1&quot; - 8.2&quot;